:root {
    --primary-dark: #0D1B2A;
    --secondary-dark: #1B263B;
    --accent-blue: #1E90FF;
    --accent-purple: #8A2BE2;
    --accent-green: #32CD32;
    --text-color: #FFFFFF;
    --golden-ratio: 1.618;
  }

  * {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }

  body {
    background-color: var(--primary-dark);
    color: var(--text-color);
    font-family: 'Roboto', sans-serif;
    line-height: 1.6;
    overflow-x: hidden;
  }

  .container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
  }

  header {
    background: linear-gradient(135deg, var(--primary-dark), var(--secondary-dark));
    padding: 2rem 0;
    text-align: center;
    position: relative;
    overflow: hidden;
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.3);
  }

  header::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('https://images.gptkong.com/demo/sample1.png') center/cover no-repeat;
    opacity: 0.1;
    z-index: 0;
  }

  .header-content {
    position: relative;
    z-index: 1;
  }

  h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
    background: linear-gradient(90deg, var(--accent-blue), var(--accent-purple));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    text-shadow: 0 2px 10px rgba(30, 144, 255, 0.3);
  }

  .tagline {
    font-size: 1.2rem;
    color: rgba(255, 255, 255, 0.8);
    margin-bottom: 2rem;
  }

  .notice {
    background: rgba(30, 144, 255, 0.2);
    padding: 1rem;
    border-radius: 8px;
    border-left: 4px solid var(--accent-blue);
    margin: 2rem 0;
    animation: pulse 2s infinite;
  }

  @keyframes pulse {
    0% { box-shadow: 0 0 0 0 rgba(30, 144, 255, 0.4); }
    70% { box-shadow: 0 0 0 10px rgba(30, 144, 255, 0); }
    100% { box-shadow: 0 0 0 0 rgba(30, 144, 255, 0); }
  }

  .nav-tabs {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin: 2rem 0;
    flex-wrap: wrap;
  }

  .nav-tab {
    padding: 0.8rem 1.5rem;
    background: rgba(27, 38, 59, 0.7);
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 500;
    position: relative;
    overflow: hidden;
  }

  .nav-tab::before {
    content: "";
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(30, 144, 255, 0.3), transparent);
    transition: all 0.5s ease;
  }

  .nav-tab:hover::before {
    left: 100%;
  }

  .nav-tab:hover {
    background: var(--accent-blue);
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(30, 144, 255, 0.3);
  }

  article {
    background: rgba(13, 27, 42, 0.8);
    border-radius: 15px;
    padding: 3rem;
    margin: 3rem 0;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    position: relative;
    overflow: hidden;
  }

  article::after {
    content: "";
    position: absolute;
    top: 0;
    right: 0;
    width: 300px;
    height: 300px;
    background: radial-gradient(circle, rgba(30, 144, 255, 0.1) 0%, transparent 70%);
    z-index: 0;
  }

  h2 {
    font-size: 2rem;
    margin: 2rem 0 1.5rem;
    color: var(--accent-blue);
    position: relative;
    padding-bottom: 0.5rem;
  }

  h2::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100px;
    height: 3px;
    background: linear-gradient(90deg, var(--accent-blue), transparent);
  }

  h3 {
    font-size: 1.5rem;
    margin: 1.5rem 0 1rem;
    color: var(--accent-purple);
  }

  p {
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
    line-height: 1.8;
    color: rgba(255, 255, 255, 0.9);
  }

  .image-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin: 3rem 0;
  }

  .image-card {
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2);
    transition: all 0.3s ease;
    position: relative;
  }

  .image-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.3);
  }

  .image-card img {
    width: 100%;
    height: auto;
    display: block;
    transition: transform 0.5s ease;
  }

  .image-card:hover img {
    transform: scale(1.05);
  }

  .image-card::after {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(to bottom, transparent 60%, rgba(0, 0, 0, 0.7));
  }

  pre {
    background: rgba(27, 38, 59, 0.8);
    border-radius: 10px;
    padding: 1.5rem;
    margin: 2rem 0;
    overflow-x: auto;
    box-shadow: inset 0 0 10px rgba(0, 0, 0, 0.5);
    border-left: 4px solid var(--accent-green);
    position: relative;
  }

  pre::before {
    content: "CSS";
    position: absolute;
    top: 0;
    right: 0;
    background: var(--accent-green);
    color: var(--primary-dark);
    padding: 0.3rem 1rem;
    border-bottom-left-radius: 5px;
    font-size: 0.8rem;
    font-weight: bold;
  }

  code {
    font-family: 'Courier New', monospace;
    color: var(--accent-green);
    font-size: 0.9rem;
  }

  .summary {
    background: rgba(27, 38, 59, 0.5);
    border-radius: 15px;
    padding: 2rem;
    margin: 3rem 0;
    border-left: 5px solid var(--accent-purple);
    position: relative;
  }

  .summary::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('https://images.gptkong.com/demo/sample6.png') center/cover no-repeat;
    opacity: 0.1;
    z-index: 0;
    border-radius: 15px;
  }

  .summary-content {
    position: relative;
    z-index: 1;
  }

  footer {
    background: linear-gradient(135deg, var(--secondary-dark), var(--primary-dark));
    padding: 3rem 0;
    text-align: center;
    margin-top: 5rem;
    position: relative;
  }

  footer::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('https://images.gptkong.com/demo/sample12.png') center/cover no-repeat;
    opacity: 0.1;
    z-index: 0;
  }

  .footer-content {
    position: relative;
    z-index: 1;
  }

  .footer-links {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin: 2rem 0;
    flex-wrap: wrap;
  }

  .footer-link {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    transition: color 0.3s ease;
  }

  .footer-link:hover {
    color: var(--accent-blue);
  }

  @media (max-width: 768px) {
    h1 {
      font-size: 2rem;
    }
    
    article {
      padding: 2rem;
    }
    
    .image-grid {
      grid-template-columns: 1fr;
    }
  }